Conservative MPs have accused senior Eurosceptic Sir Bill Cash of fuelling violence against politicians after he accused Theresa May of “abject surrender” and “capitulation” to the EU.

Former cabinet minister Nicky Morgan said Sir Bill’s words were “not helpful” while former Foreign Office minister Alistair Burt accused the veteran MP, a senior member of the European Research Group of anti-EU Tories, of a publishing “a vain and bitter article”.

MPs will return to Westminster after their Easter break on Tuesday with no solution to the Brexit crisis in sight. Cross-party talks have so far failed to reach an agreement and the UK is on course to take part in EU elections on 23 May, despite the government insisting it can pass a Brexit deal before then.

With the House of Commons gripped by deadlock and her deal having been rejected by MPs three times, Ms May was forced to agree another Brexit delay with the EU earlier this month. The UK is now set to leave the bloc on 31 October.

Writing in TheSunday Telegraph, Sir Bill said this was an “abject surrender” and accused the prime minister of ”capitulation” and “appeasement”.

The comments were strongly condemned by pro-EU Tories.

Ms Morgan, a former education secretary, told BBC Radio 4’s Today: “I understand that Sir Bill Cash has written an article in which there are all sorts of phrases about betrayal and capitulation and all the rest of it.

“As my colleague Alistair Burt has pointed out, this kind of language is not helpful. It’s not the kind of language that our councillors or frankly any normal people would use.”

The MP, who has received death threats, said she saw a link between the type of comments made by Sir Bill and violence directed against MPs.

Asked if she believed there was a connection, she said: “I do. I think it’s been shown that the language that MPs or campaigners, mainly in favour of Brexit, are using is stoking up other people, often who are sitting at home watching all this stuff and it gets them really, really angry and fired up and then they say things that they would never say face to face.”

She added: “Language is important and the One Nation group of MPs that I am co-chairing has said very clearly that we should all think about the language that we are using in these debates. We need to remember that politics is about much more than Brexit.”

Mr Burt, who resigned as a Foreign Office minister last month in order to vote against the government on Brexit, wrote to Sir Bill on Twitter: “A vain and bitter article focused on your prime minister, with your opinions expressed in words such as mendacity, surrender, betrayal, appeasement, bended knee...Does it ever cross your mind what you’re contributing to?”

In his article, Sir Bill’s wrote: “In the early hours of 11 April, Theresa May made a statement in Brussels after her abject surrender to the European Council – now a constant feature of her capitulation and of our humiliation throughout these withdrawal negotiations.

“She stated that she had ‘agreed an extension of time’. This was no agreement, it was appeasement on bended knee. Our ambassador to the EU even entwined it in his letter of submission to the decision of the European Council thus purporting to make it an international treaty. Under the so-called ‘agreement’ we were tied down by conditions like Gulliver.”

He added: “How low can we sink with the prime minister making us crawl on our hands and knees, not only to the EU, but to Germany and France?”

Conservative MPs are plotting how to oust Ms May and on Tuesday will discuss proposals for changing party rules to allow another vote of no confidence in the prime minister.

Under current rules, a confidence vote in the party leader can only be held once a year. Ms May saw off an attempt to topple her in December, meaning another vote cannot be held until the end of the year.